1. Field of the Invention
The invention relates to an electrolyte and its precursor, and more specifically to a gel polymer electrolyte and its precursor.
2. Description of the Related Art
Among portable electronic products, a lithium rechargeable cell is popular due to its light weight, high voltage and high energy density. With development of electronic products continually moving towards thinner profiles and increased flexibility, use of polymer electrolyte in lithium rechargeable cells have become more popular.
Lithium rechargeable cells utilizing polymer electrolyte can be effectively applied in commercial electronic products because the cells have no electrolyte leakage, a thin profile, a multi-angle, a light weight, low vapor pressure and low self-discharge.
To achieve flexible and thin cells, some gel-type polymer materials combined with electrolyte compositions have been developed, for example, polyethylene oxide (PEO), polymethyl methacrylate (PMMA), polyvinylidene difluoride (PVDF), polyaniline (PAN) and derivatives or copolymers thereof. The conventional fabrication of the gel-type polymer electrolyte utilized in a polymer cell is described as follows. After filming and removal of solvent, the polymer film is interposed between active substance layers or coated thereon to form a cell core. A liquid electrolyte is then filled to adhere to the electrode plates. When charge/discharge, lithium ions are inserted and removed, reducing expansion and contraction of the laminated electrode plates, thus, prolonging cell lifetime. However, the described conventional fabrication method is complex.